Neptune, named for the Roman god of the sea, is the furthest planet from Earth in our solar system. Neptune is the only planet in the solar system that can’t ever be seen with the naked eye. Other planets, like Uranus, might prove very challenging to see, but with good eyesight and the right conditions, it’s possible. Neptune is nearly twice as dim as Uranus, in part because it’s so much further away.
Luckily, with a magnitude of anywhere from 7.6 to 8.0, Neptune is still visible with the right equipment assisting your eyes. Realistically, you’ll need to look for Neptune through a telescope if you want a chance of seeing the planet. A pair of strong binoculars just might cut it, but either way, you’ll need to be armed with the proper knowledge to get a good look at the furthest planet from the sun. We’ve got everything you need to know down below.
Can you see Neptune with a Telescope?
Neptune is over 2.8 billion miles away from the Earth. Even at the speed of light, that’s quite a distance. For reference, it takes about eight minutes for the sun’s light to reach Earth, but it takes over four hours for that light to reach Neptune. Because of its incredible distance, you need to look at Neptune through a telescope to see it. With a powerful pair of binoculars, you might be able to see the planet, but it would almost certainly look like any other star out in the cosmos. If you were lucky, you’d be able to distinguish a blue tint emanating from the “star”.
Finding Neptune in the Night Sky
Finding Neptune can be challenging the very first time, but finding it on successive nights gets easier and easier. That’s because Neptune hardly changes its position in the night sky. Neptune is so far from the sun that it makes one full revolution every 165 years. Earth is more or less running laps around the big blue giant.
Because it moves so slowly, Neptune will spend the entirety of 2021 within the Aquarius constellation. Towards the end of the year, the planet will get very close to Pisces, but it will still remain in relatively the same place.
It’s a good idea to consult some stargazing charts, either in a book or on a phone app, before trying to spot Neptune. The charts will help you know exactly where to look to find Neptune. Remember that all year long you’ll want to be looking near Aquarius to find the planet.
When can you see Neptune in your home telescope?
At the beginning of the year, Neptune is visible only in the early evening. It drops below the horizon by nine at night, so your best chance to see the planet in January is just after sunset. After that, you won’t have an opportunity to see Neptune for a little while. From February through May, Neptune is so close to the sun that you won’t be able to see it in the night sky.
Neptune will return to visibility at the beginning of June. At that point, the planet will be visible just before dawn. Any morning bird astronomers will want to take advantage of those early hours to get a look at Neptune through a telescope. Neptune will steadily become visible earlier and earlier as the summer months progress.
Through August and September, Neptune will be visible all night long. After that, Neptune will go back to being an evening planet. By November, it will only be visible for about half the night. By December, Neptune will set before ten o’clock. Luckily, Neptune’s shift to evening visibility lines up with the earliest sunsets of the year. Even in November and December, you should have plenty of time to get a look at Neptune through a telescope.
How To Get The Best View of Neptune
Because Neptune is very far from Earth and very dim in the sky, you’ll want to get as large a telescope as possible to get your best view of the planet. Without having an industrial-grade telescope, you won’t be able to see very much of Neptune at all.
Again, consult star charts to find out exactly where you need to look in the night sky during your observation window. After that, use your finderscope to aim where you think Neptune may be. You’ll need to look through the eyepiece of your telescope to actually see the planet, which won’t be much more than a point of light in the night sky.
With a standard home telescope that goes to 100x magnification, you’ll be able to see Neptune as a small, bluish star. The color will let you know that you’ve found the actual planet. Neptune’s atmosphere contains an incredible amount of methane gas, which absorbs red light and causes the planet to reflect back blue light.
If you have a larger, more powerful telescope, you can increase the magnification once you’ve found the blue glow of Neptune. At that point, you should be able to see, rather than a pinprick of light, a flat, blue disc. Finding the disc is your confirmation that you’ve definitely found the planet.
When a planet enters opposition, it is directly opposite the Earth, meaning astronomers have their best view of it all year. In 2021, Neptune will enter opposition on the 14th of September. Neptune’s opposition isn’t as dramatic as the opposition of other planets, so it will likely look the same in August as it does in September. For several weeks on either side of its opposition, Neptune will be visible all night long.
After its opposition, Neptune will once again become an evening planet. It will begin to set earlier and earlier in the night. By November, Neptune will be visible from sunset until around midnight. In December, Neptune will set by ten o’clock at the latest, as it works its way back to setting by nine o’clock in January.
If you aren’t one for early mornings, try to catch Neptune in the later months of this year. Remember that for several weeks on either side of Neptune’s opposition, you’ll be able to see the planet through a telescope at any time throughout the night.
What Does Neptune Look Like Through a Telescope?
Neptune has a number of exciting features on its surface. The planet appears blue because huge quantities of methane gas in its atmosphere absorb all the red light from the sun and reflect the leftover blue light. The two major surface features of Neptune are the Great Dark Spot and the Bright Smudge, which are parts of a storm on Neptune’s surface that is the size of the planet Earth.
Unfortunately, with your home telescope, you won’t be able to see any of the surface features of Neptune. The planet is simply too far away for most commercially available telescopes to be able to keep up. However, that doesn’t mean you won’t be able to see the planet.
Through your telescope at standard magnification, Neptune will look like a regular star that glows blue. Once you’ve found what you think might be Neptune, you should increase your telescope’s magnification. At 200x magnification, Neptune should come into focus not as a tiny point of light, but as a flat blue disc.
From your home, you won’t be able to get a more refined view, but seeing the disc confirms you’ve found Neptune, which is a remarkable accomplishment for an amateur astronomer.
Which telescope is best for observing Neptune?
Almost any telescope will be able to at least see Neptune. There are a few qualities, however, that make a telescope ideal for spotting Neptune and the other planets. You’ll want to find a telescope with a long focal length, generally called a “slow” telescope. That’s because you need to focus on only a very small bit of the sky to see Neptune through a telescope. You don’t want a telescope that gives you a wide, general view of the cosmos.
You should also make sure that your telescope has at least 200x magnification. If you want to be able to see Neptune as a disc, to really confirm that you’ve spotted the planet, you need to be able to use at least that level of magnification. Anything less, and the only way you’ll be able to tell Neptune apart from a star will be by its bluish hue.
Can You Spot Neptune’s Moons?
Neptune has fourteen confirmed moons. The largest and most famous of these is Triton, which is the seventh biggest satellite in the solar system. Triton also standouts as being the only moon in the entire solar system that orbits its planet against the direction of the planet’s spin.
Unfortunately, you won’t be looking at Triton through your home telescope. The moon is almost twice as dim as Neptune, meaning it’s outside the capabilities of anything other than a research-focused telescope.
There is everything you need to know to be prepared for finding Neptune through a telescope. Soon the planet will become visible again, so there’s no better time than now to get ready for some planet spotting!
My first goal when I picked up my first telescope was to observe every planet through a telescope. Over my many years of stargazing, I have learned little tips and tricks for getting the best views of the planets. Which led me to compile a guide for Venus, Mars, Saturn, Jupiter, Mercury, Uranus to help you get the best views of our planets.